Lensed optical connector

Abstract

A low light loss expanded beam fiber optic connection is provided comprising lensed optical connector pins. Each connector pin employs a cylindrical housing in which a fiber end is precisely located along a longitudinal axis in precisely spaced relationship with an adjacent ball lens. The center of the ball lens is coaxial with the longitudinal axis of the optical fiber core and is maintained in such precisely spaced relationship by means of a spacer engaging the ball lens and the fiber end on opposed surfaces. As a result of the precise relationship, light emanating from a fiber end is disposed at the focal point of the adjacent ball lens for transmission to an adjacent, axially aligned lensed optical connector pin of similar construction.

What is claimed is: 
     
       1. An optical connector comprising a precision fiber alignment guide for locating the end of an optical fiber along a precise longitudinal axis; a ball lens formed of a material having a refractive index of less than 2, one end of said alignment guide having a flat face and being in spaced relation relative to the ball lens whereby the terminal end of an optical fiber disposed in the plane of said alignment guide one end is located at substantially the focal point of said ball lens at the flat face of the alignment guide; spacer plate means having at least one flat face and positioned between the ball lens and said alignment guide for engaging and maintaining the alignment guide one end and said ball lens in said spaced relation, the flat face of the alignment guide abutting the flat face of the spacer plate means, in which said spacer plate means has an opening formed therein for the unobstructed passage of light relative to a terminal end of an optical fiber located in said precision alignment guide. 
     
     
       2. The connector of claim 1 in which said spacer plate means opening widens from the flat face in the direction of said ball lens; a peripheral portion of said ball lens protruding into the said opening and locating the ball lens center in substantial alignment with the center of said spacer means opening. 
     
     
       3. The connector of claim 2 in which the smaller end of said opening in said spacer plate means is substantially circular and coaxial with the central longitudinal axis of said precision fiber alignment guide; said smaller end being of a diameter larger than that of the clad, lightconducting core of an optical fiber adapted to be received in said precision guide, and smaller than the outer diameter of such optical fiber. 
     
     
       4. An optical connector as claimed in olaim 1 wherein the alignment guide is constructed by a jewel material and the spacer plate is constructed selectively of glass or metal. 
     
     
       5. An optical connector as claimed in claim 1 wherein the flat face end of the spacer plate means is adapted to abut against the terminal end of the optical fiber. 
     
     
       6. An optical connector as claimed in claim 1 wherein both faces of the plate are flat and wherein the pin housing includes a terminal end of reduced diameter thereby to secure the ball between the plate face and the terminal end. 
     
     
       7. An optical connector comprising a precision fiber alignment guide for locating the end of an optical fiber along a precise longitudinal axis; a ball lens formed of a material having a refractive index of less than 2; one end of said alignment guide being in spaced relation relative to the ball lens whereby the terminal end of an optical fiber disposed in the plane of said alignment guide one end is located at substantially the focal point of said ball lens; spacer means positioned between the ball lens and said alignment quide for engaging and maintaining the alignment guide one end and said ball lens in said spaced relation, a pin housing for receiving said ball lens and said precision fiber alignment quide; said housing being of a size and configuration to maintain the center of said ball lens substantially coaxial with the precise longitudinal axis of said precision guide, said housing having a first axial bore for receiving said ball lens, said spacer means, and said precision guide; a second axial bore in said housing having a diameter different from said first axial bore and coaxial with said first axial bore; a housing shoulder defining the juncture between said first and second axial bores; a liner for said pin housing having an axial passageway for passage of an optical fiber end disposed in said second axial bore engaging said shoulder at one liner end limit; one end of said precision alignment guide engaging the end of said liner engaging the pin housing shoulder. 
     
     
       8. The connector of claim 7 in which an optical fiber is disposed in the axial passageway of said liner and a contiguous optical fiber portion is received in said precision alignment guide and terminates substantially at the interface between the end of said precision alignment guide engaging said spacer means and said spacer means. 
     
     
       9. The connector of claim 8 in which the optical fiber portion disposed in said liner is contiguous with an optical fiber portion having a protective covering thereover, and an outer peripheral wall portion of said housing is crimped into engagement with said protective covering of said optical fiber. 
     
     
       10. The connector of claim 9 in which said protective covering is plastic and heat is applied in the course of crimping the housing peripheral wall portion, whereby said covering of said optical fiber is melted and interlocks with the deformed housing portion. 
     
     
       11. The connector of claim 8 in which the optical fiber portion disposed in said liner is contiguous with an optical fiber portion having a protective covering thereover and an opening is in the pin housing periphery surrounding the optical fiber portion having the protective covering thereover, for admission of an adhesive for securing the protective covering of said optical fiber in place to an inner portion of the pin housing. 
     
     
       12. The connector of claim 7 in which portions of the housing in which said ball lens is disposed are formed over peripheral portions of said ball lens for retaining said ball lens in said housing first axial bore in abutting engagement with said spacer means. 
     
     
       13. The connector of claim 7 in combination with an alignment sleeve having an aligning bore for receiving and axially aligning said connector housing; said connector housing having an outer peripheral stop shoulder for engaging a first receiving end of said sleeve defining said aligning bore and limiting entry of said connector housing into said aligning sleeve. 
     
     
       14. The connector of claim 13 in combination with a second optical connector housing received in a second receiving end of the aligning bore of said aligning sleeve; the ends of said connector housings having substantially identical ball lenses mounted therein and engaging in a butt contact; the ball lenses being spaced apart an interval comprising a fraction of the diameter of said ball lenses with said housings in abutting engagement. 
     
     
       15. A connector body having a plurality of passageways disposed therein in which a plurality of aligning sleeves are mounted for reception of a plurality of abutting connector housings of claim 14 for effecting a plurality of light transmissive connections. 
     
     
       16. The connector body of claim 15 in which a plurality of electrical connections are effected in some aligning sleeves mounted in said connector body simultaneously with said light transmissive connections effected in other of said aligning sleeves. 
     
     
       17. The connector in claim 7 in which said spacer means has an opening formed therein for the unobstructed passage of light relative to a terminal end of an optical fiber located in said precise guide. 
     
     
       18. The connector of claim 17 in which said spacer means opening widens in the direction of said ball lens; a peripheral portion of said ball lens protruding into the said opening and locating the ball lens center in substantial alignment with the center of said spacer means opening. 
     
     
       19. The connector of claim 18 in which the smaller end of said opening in said spacer means is substantially circular and coaxial with the central longitudinal axis of said precision fiber alignment guide; said smaller end being of a diameter larger than that of the clad, light-conducting core of an optical fiber adapted to be received in said precision guide, and smaller than the outer diameter of such optical fiber. 
     
     
       20. An optical connector comprising a pair of optical connector pins; each of said pins having a housing with a precision fiber alignment guide located within said housing for positioning the end of an optical fiber along a precise longitudinal axis; the guide end having a flat face in alignment with the end of the optical fiber; a ball lens formed of a material having a refractive index of less than 2 and positioned in an end portion of said housing; the flat face end of said alignment guide being in spaced relation relative to the ball lens whereby the terminal end of an optical fiber disposed in the plane of said alignment guide one end is located at substantially the focal point of said ball lens; spacer plate means positioned between the ball lens and said alignment guide for engaging and maintaining the alignment guide flat face end and said ball lens in said spaced relation, said spacer plate means having a flat face for abutment against the flat face end of the alignment guide; said spacer plate means, alignment guide, and ball lens being received within said housings in concentric axial alignment; means in said pin housing for locating said precise alignment guide relative to the opposed ends of said housing; means maintaining said ball lens, spacer plate means, and alignment guide in a state of assembly; and alignment sleeve means for slidably receiving two optical connector pins with the pin ends in which said ball lenses are located in abutting engagement whereby said pins are maintained in concentric axial alignment. 
     
     
       21. The optical connector of claim 17 in which said pin housings, spacer means, and precision fiber alignment guides are of generally cylindrical configuration and each precision alignment guide is located at a precise interval relative to the end of the pin housing in which said ball lens is disposed. 
     
     
       22. The optical connector of claim 17 in which each spacer means is centrally apertured for passage of light and is formed of a non-transparent material. 
     
     
       23. A method of forming an optical connector comprising the steps of forming ball lenses of uniform diameter from a material having a refractive index of less than two; determining the interval between the center of the ball lens and the lens focal point; locating a optical fiber end in a precision fiber alignment guide; forming spacers with a flat face and of such configuration and size so as to abut a ball lens and optical fiber end on opposed surface portions and locate the optical fiber end substantially at the focal point of the ball lens when the center of said ball lens and the optic fiber central axis are axially aligned, abutting the optical fiber end and a flat face of an end of the fiber alignment guide, and mounting the ball lens, spacer and optical fiber end in a housing in abutting engagement in said axial alignment.